29 May 2007

So the blog'o'sphere is abuzz with discussion of a New York Times piece by Edmund Andrews about proposed subsidies for Fischer-Tropsch production of benzene from coal in order to fuel oversize pickups. Call it the antithesis of demand-side management. Generally speaking the idea of large scale F-T coal-to-liquids is a program that makes corn ethanol look like a model of efficiency.

For one thing, I don't see how this adds to the USA's energy security. The F-T process is a net energy loser, and it's not like the USA is a major coal exporter. According to the Energy Information Administration statistics on coal the USA exports about 50 Mtons of coal, imports 30 Mtons, and produces about 1200 Mtons. This means the USA's net coal exports only amount to 1.7 % of total production. While the USA may have the worlds largest coal reserves, historically coal reserve numbers haven't proven to be very accurate and it certainly doesn't look like there's a lot of spare capacity.

This also puts paid to the fig leaf of carbon dioxide sequestration. While coal-fired electricity can claim they are working on sequestration, F-T fuel really can't sequester their product, only the inefficiencies in producing it. As such, they will make themselves even more vulnerable to acquisitions accusations that they are cooking the planet then they already are.

So it would seem that the proposal is to trade away the USA's self sufficiency in electricity production in order to slightly reduce oil imports. What's more important, fueling your car or heating your house? Of course, coal executives don't care about the average consumer, they care about their profits. However, I'm not sure why the American taxpayer should subsidize this. What do the American people get from this? A quote from the NY Times article is illustrative:

But coal executives anticipate potentially huge profits. Gregory H. Boyce, chief executive of Peabody Energy, based in St. Louis, which has $5.3 billion in sales, told an industry conference nearly two years ago that the value of Peabody’s coal reserves would skyrocket almost tenfold, to $3.6 trillion, if it sold all its coal in the form of liquid fuels.

So what's the obvious side effect here? Higher electricity prices, obviously. The cost of coal constitutes about 50 % of the cost of coal-fired thermal electricity generation. Hence, if the value of coal shoots up by a factor of ten as suggested the price of coal-fired electricity should go up 5-fold. The coal executives would be giveing a gift to their competition. Nuclear, wind, and solar power would quickly become more competitive and start to displace coal-fired generation. The last thing the coal industry should logically want is to encourage the installation of more wind and solar power; these industries have learning rates that will eventually push their cost below that of coal. Why would an coal executive hasten that? One can certainly imagine that if enough coal is displaced, the price will again crash. Hence they coal executive might in the end have all the coal they want to produce F-T benzene. This is assuming their corporations survive the roller-coaster ride they are setting themselves up for and don't go bankrupt.

15 May 2007

Historically the photoelectric effect has been known for a couple hundred years ever since it was observed in elemental Selenium around the turn of the 19th century. It became practical to use the photoelectric effect to generate power with the development of the transistor in 1947 that lead directly to Germanium (and later Silicon) solar cells that could produce a useful amount of electricity. Early solar cells saw use in extreme applications, such as providing power for satellites. Serious efforts to develop photovoltaic cells for commercial power production wasn't undertaken until the Arab oil crisis's of the 1970s. The USA developed an early dominance in the technology, but that advantage withered as the memory of the oil crisis faded from public view and successive administrations ignored the technology. More recently interest in photovoltaics has been rekindled due to concern around global warming, predominately supported by programs in Germany and Japan, whose domestic manufacturers now produce the bulk of solar cells. Research and development in photovoltaic technology is proceeding at a frenzied pace, as triple-junction thin-film silicon and Copper-Indium-Gallium-Selenide (CIGS) cells are posed to take over market share from traditional polycrystalline silicon wafers sawed from solid ingots. In the future decades, nanotechnology and organic semiconductors offer the potential for new generations of solar power technology.

Photovoltaic cells are not like any other method humanity uses to collect and use energy. Existing techniques extract energy either from mechanical motion (wind, hydroelectric, tidal) or heat differentials (fossil fuels, nuclear, solar-thermal). Whereas all these systems produce useful work by the turning of a shaft photovoltaics convert sunlight directly into direct-current electricity. While photovoltaics are still beholden to the laws of thermodynamics and entropy, the difference still implies that they abide by difference rules. In particular, they have a total absence of moving parts and as a result are almost free of maintenance requirements. Photovoltaic cells degrade in performance only very slowly as they are bombarded by cosmic rays. Most manufacturers offer warranties that guarantee they will still reach 80 % of their rated power output after 25-years.

Photovoltaic Share of the Energy Pie

A report by Merill Lynch (Hat-tip to Clean Break) found that between 2200-2500 MWpeak worth of solar cells were manufactured in 2006 [1]. Taking the median value of 2350 MWpeak and a capacity factor (cf) of 0.2, which is typical, then the annual electricity capacity was 4 million kWh. According to the Energy Information Administration (US DoE), the world produced 16,400 billion kWh of electricity in 2004, and that figure is growing at 3.2 % a year since 1994. If we extrapolate to 2006 at 4 % growth then the total electricity production was an estimated 17,950 billion kWh. Photovoltaic power consists of only about 0.6 % of the annual growth in electricity capacity.

It seems minute, and it is, for now. However, solar production hasn't been growing at 3.2% per year. It has, in fact, been growing at 33 % per annum for the last decade [2], and it's expected to continue that trend for the immediate future. The cumulative installed capacity can be expressed as

C(t) = Coe(γ-δ)(t-to)/(γ-δ)

where C(t) is the cumulative installed PV electricity generation capacity, Co is the initial installed capacity, γ is the growth rate, δ is the degradation rate (10 % efficiency loss every 12.5 years or 0.008), and t is of course the time in years. Nothing fancy here, just pure exponential growth.

Figure 1: Scenarios for PV cumulative installed capacity as comparedto worldwide demand growth of 4 % per annum over the next 25 years.

As one can see from Figure 1, while the impact of solar may be trivial now, it will not be over the next 25 years. If solar can maintain the same growth rate is has for the past decade, solar can supply all of mankind's projected electricity demands 26 years from now.

Cost of Photovoltaic-derived Electricity

Generally speaking the cost of any technology declines with production capacity according to a power-logarithm law,

P(t) = Po ρlog2( Exp( γ (t-to) )

where P(t) is the price as a function of time, Po is the initial price, ρ is the learning rate, and C(t) is the capacity. Historically, ρ for photovoltaics has been very stable around 0.8 which corresponds to a learning rate of 20 % as depicted in Figure 2.

Figure 2: Learning rate for photovoltaic panels (reprinted from [3]).

The learning rate of photovoltaics is much higher than that of other energy technologies. In fact, it's more in-line with things like computers or DVD players. This fact should surprise no one; as I mentioned in the introduction, photovoltaics are different from all other forms of energy production. The small incremental nature of photovoltaics is a major advantage from a R&D perspective, as I've described previously. While coal and nuclear power plants are installed in increments of hundreds or thousands of megawatts, solar panels are measured in the hundreds of watts. Thus while a design change to a nuclear power plant can take a decade or more to manifest itself, solar manufacturers can do this in weeks. As a result, photovoltaic technology will go through hundreds of design revisions in the time it takes coal or nuclear plants to go through one. Some learning rates for various technologies are listed in Table 1. One thing to take from the table is not only that photovoltaics have a superior learning rate, but that they also have so much further to grow.

Current panel costs are treading at around $4.80/Wp, and the various extras such as frames, labour cost an addition $2.50/Wp. I'll use two locations to establish a baseline for the cost of photovoltaic power: Stuggart, Germany and Los Angeles, USA. A Retscreen analysis shows that the Stuggard location produces 1.089 MWh/year /kWp (which represents a capacity factor of 0.17) and LA produces 1.605 MWh/year /kWp (capacity factor 0.25). Simulations in RETSCREEN find that amortized over 25 years these locations can produce power at $0.24/kWh in Stuggart and $0.21/kWh in California [4]. Financial assumptions are: energy inflation is equal to monetary inflation, interest is 1.0 % above prime (government rates).

World residential electricity prices are generally lower than this [5]. France, which is primarily nuclear, has a rate of $0.144/kWh. The USA, which is coal based, has a mean rate of $0.095/kWh. Canada, which is mostly hydroelectric is one of the lowest at $0.068/kWh; another hydroelectric nation, Norway, comes in at $0.071/kWh. All of these numbers will include associated transmission costs. When we use the growth curves shown previously in Figure 1 with our equation for price, we find that the cost of PV drops below that of conventional electricity generation startlingly fast (Figure 3).

Interestingly, the location of photovoltaics has little impact on their price over the long term. Rather it is the industy's growth rate which dictates the future price. One might be curious as to where the price point might be when the industry saturates.

The actual price decline of PV has stalled over the past year and a half. Essentially what happened is the PV industry eclipsed the microelectronics industry in terms of silicon consumption before thin-film silicon technologies were ready for commercial production. As a result, there's been a bit of a lag as silicon producers catch up to demand. I do not think that this will continue to be a problem, as I will explain below.

Limitations to Growth

For one to look at the curves in the previous sections, and believe that they are achievable then assurances that there won't be too many roadblocks in the future. This section will take a closer look at potential issues that could slow the growth of the photovoltaic industry.

Economic IncentivesOne of the issue with photovoltaics is that as an emergent technology it isn't cost competitive with fossil fuels today. However, subsidy programs by governments of Japan and Germany have been generating tremendous demand growth by making solar cost competitive. Recently more jurisdictions have put forth subsidy programs, such as California, New Mexico, Ontario, Spain, Italy, and Portugal. One obvious question in looking at the exponential growth curves in Figure 1 is, "Just how much is all of this going to cost?" Combining the equations for the learning rate with the growth rate provides us with an answer.

Psubsidy = (Po ρlog2( exp() ) - 0.05)* C(t-to) e(γ-δ)(t-to) / (γ-δ)

This assumes that existing installations are amortized at the same rate as the price of new modules drops. This is not a bad assumption simply due to the massive growth rate, which has a doubling time of 2.1-2.7 years.

Figure 4: Annual cost to subsidize entirety of world PV production to arate of $0.05/kWh under 33 % annual growth scenario.

Figure 5: Annual cost to subsidize entirety of world PV production to a rate of $0.05/kWh under 25 % annual growth scenario.

The total cost of these subsidies run to about US$90 billion for the 33 % growth model and US$154 billion for the 25 % model until the price of solar power drops below the desired $0.05/kWh. It's not an insignificant amount of money, but neither is it a particularly onerous cost for transforming our energy structure; the USA alone budgets $24 billion a year to the Department of Energy.

It's probably worth noting that return rate is over one trillion dollars a year by 2031 against the $0.05/kWh baseline. This can be construed either as potential tax revenue or additional income that will be contributed to GDP.

IntermittencyIntermittency is the problem that renewable energy sources suffer from due to the natural fluctuations of their power source. Any transmission grid that relies on renewable sources as a primary input will require a substantial amount of storage, deferrable demand, or load-following spare capacity. The severity of intermittency can be thought of as a combination of its predictability, correlation to demand, and variance. Compared to its chief competitor, wind, solar is far more predictable. One can be assured of the position of the sun in the sky every day with the mitigating factor being cloud cover. However, integrated over a large area the portion of the sky covered with cloud can be reliably estimated. In comparison, wind velocity is nearly impossible to predict. It also correlates relatively well to the natural daily peak in demand, for a noisy real-world system. The variance of wind and solar are roughly equal, which is a little surprising given the dinural cycle of night and day that solar has to deal with. In addition to their daily variance both solar and wind are subject to seasonal variations.

It is my opinion that the concern over intermittency of solar power is exaggerated. This is due to the fact that the learning rate of photovoltaics dictates that the cost of solar will fall below that of the main established sources of power (coal, nuclear) well before solar will constitute a significant fraction of our energy consumption. I think most people will agree, when the price of solar energy drops below that of the competition, the game changes. When you have power to burn, simple and low-capital techniques of storing or transmitting solar electricity become practical. At $0.05/kWh solar would have a margin of $0.04/kWh or more to work within for charging electric vehicles, filling deferrable demand, storage techniques such as Vanadium redox batteries, or long distance high-voltage direct-current transmission.

Resource LimitationsOne of the factors limiting photovoltaic growth at the moment is a shortage of electrical-grade refined silicon. Silicon itself is not in short supply, being the second most abundant element in the Earth's crust after Oxygen. This limitation is likely to fall away as new cell designs that use less silicon are deployed commercially. Traditional cells are made by sawing a solid block of polycrystalline silicon and then polishing the surfaces. This results in a cell that is 300 μm with around 50-100 μm of material wasted. New techniques such as ribbon growth can reduce that figure to 100 μm. Furthermore, thin film silicon cells grown by chemical vapour deposition, such as Sharp's triple-junction cells, can achieve the same performance as polycrystalline cells with only 10 μm of silicon. As these techniques reach market penetration (ribbon growth is proprietary, thin-film techniques are not), they should reduce the strain on silicon refiners.

The other resource restriction is due to geographical limitations. Some renewable resources (hydroelectric, tidal) are tightly limited to certain terrain, such as tidal basins or river valleys. Wind is a somewhat more diffuse, but the best resources where the wind blows most strongly and consistently are still limited compared to humankind's energy consumption.

Figure 6: Global Solar Energy Abundance Map [6].

World insolation (incoming solar radiation) on the other hand is massive and relatively evenly distributed. The sun outputs 1026 watts of power and our tiny little planet intercepts about a billionth of that. Right now the human race consumes around 18 TW of energy, or 1/10,000th of what strikes the Earth. Roughly 1/3rd of that is useful work, the rest is lost to entropy. The 24-hour average insolation for the inhabited world spans 150-300 W/m2. That implies we would need 3.5-7 m2 of 10 % efficient panels per person, to supply all of our energy needs from solar power.

Personnel ShortfallRunning short of trained people in a rapidly growing industry is always presents a problem. Take, for example, nuclear engineers. There aren't many of them, training one takes about four years, and their skills are not easily transferred to other disciplines. The photovoltaics industry is similar enough to the microelectronics industry that they can trade personnel, however. The microelectronics industry has already built up strong education programs that photovoltaics can piggy-back.

If chemical vapour deposition (CVD) for thin-film silicon becomes the dominant production method, this still should not present too great a problem. CVD is a common manufacturing technique used for all sorts of coatings, such as tribological (hardness) coatings for tools, or even aluminized mylar. It's also used in microelectronics. It does happen to be more of an art then a science, which means that learning requires experience.

Ancillary CostsInstalling a rack of PV modules on a garage is not simply a matter of fixing them down with some twist-ties. Typically they need a metal frame so they present an optimum azimuth to the sun, they need electrical wiring, they need an inverter to transform DC to AC power, they may need a net-meter to sell power back to the utility, and of course, there's the labour required for installation. As many readers will know, there's quite an argument in California as to whether or not a licensed electrician is required for installations. One might also consider the 3 mm layer of glass (glazing) that protects the cells from hail also 'ancillary' although it is included in the sticker price.

The main question is whether or not ancillary costs have a similar learning rate to that of the modules themselves. My analysis has assumed that they do. We will probably see declines in the ancillary costs by better product integration and standardization. Rugged encapsulation combined with light-trapping surface patterning will probably slowly replace the standard glazing. Inverters should improve drastically both in terms of cost and lifespan. There's also always been the idea of incorporating solar cells into dual-use products, such as solar shingles or skylights.

Consumer AcceptanceUnlike just about every other source of electrical generation, photovoltaic power doesn't have any "Not In My Backyard" (aka NIMBY) issues. `Nuff said.

Conclusions

Many people will look at the graphs in disbelief that the easy path photovoltaic power has been travelling can continue. All I can really say in reply is, those are the historical numbers. The learning rate is exceptionally stable. The growth rate has been, if anything, accelerating in the face of a industry silicon shortage. Thin-film technologies seem well positioned to cause the price to continue to fail into the near future. Solar power doesn't have very far to fall in many European nations before it's cheaper than residential rates. As residential solar becomes the cheapest power available that will continue to push demand upward and fuel growth. There's nothing obvious to me that says 'Stop' in solar's future and it's a fact of exponential growth that the early years matter the most. Even if the growth rate drops 1 % a year over the next 25-years the eventually outcome seems predetermined, it's just a question of the timing.

01 May 2007

Several months ago the minority Conservative federal government of Canada made a big gear-change and overhauled their environmental policy. Gone were the efforts to suppress the validity of climate change science, and in came a six-point plan encapsulated as ecoAction. The six components are based on: a biofuels initiative, a new bill on toxic chemicals and a similar clean air act for airborne pollutants. In addition there was two grab-bag programs for transportation (ecoTransport) and residential/commercial/industrial (ecoEnergy), as well as a trust-fund to fund specific programs in the individual provinces. With such 'eco' branding, my natural reaction was to assume it was a major green-washing program. Closer examination reveals a little more beef (or pork, as the program goes).

Politically, I think this sea change was arrived at for a variety of reasons. One certainly has to be the nomination of Stephen Dion as leader of the Liberal Party. Dion was previously the environment minister in the previous government and an active supporter of Kyoto and a carbon tax. The conservative greening stole much of his thunder.

Furthermore, Harper has long been accused of pushing Canada conservatism towards neo-conservative tenants. On issues such as the environment and personal freedoms they were moving out of touch with their base; As a result, they seem to have been losing votes to the Green party, which is now polling around 9-12 % nationally and gaining substantial support in rural Alberta. I think the Conservative government grew concerned with changing demographics and that their policies were risking freezing out support for them from important special interest groups. The change appeared to me to be signaled when the government moved away from the US administration and sharply criticized them over Maher Arar and his deportation from the USA to Syria and subsequent torture. Right now they are facing all sorts of trouble over insufficient oversight of Afghan prisoners handed over to the Afghan government.

In addition, political party donations from corporations has been sharply curtailed following the patronage scandals that saw the Liberal party fall from grace. That in turn will signal a welcome strengthening of the importance of individual citizens for fund raising purposes. Nor is corporate opposition to Kyoto uniform. A number of corporate leaders want some form of climate change legislation to help indemnify them from the associated liabilities.

Also, we must remember that the Conservatives are in a minority position in parliament, and much of this could be a fig leaf to gain the support of the New Democratic Party on other issues, such as the intervention in Afghanistan.

Environmental Trust

The biggest budgetary item is an environmental trust fund that is disbursing funds to the provinces, at $1.5 billion per year. To a certain extent, this is a reflection of the decentralized nature of governance in Canada. After all, the provinces are the ones with the control over electrical power generation. Basically it appears to be providing matching funds with a healthy dose of pork. For example, British Columbia is receiving funds for, "Support for the development of a, “hydrogen highway,” a network of hydrogen fueling stations for fuel celled buses and vehicles;" which is unsurprising given the presence of a (struggling) fuel cell industry in the province. Similarly, Alberta's focusing its efforts on oxymoronic 'clean coal' and sequestration.

Biofuels

The biofuel initiative appears to be an example of pure pork, with $200 million in subsidies to ethanol and biodiesel producers and $145 million for research, probably centered around cellulosic ethanol (-cough- Iogen -cough-). The goal is E5/B5 by 2010.

Chemical Regulation

Environment Canada has been engaged in a program since 1999 to categorize a wide variety of chemicals used in industry and to produce goods for human consumption to gauge how hazardous they are. Chemicals are categorized on whether they are persistent and bioaccumulative. Essentially, the database is at the point now where they can start implementing some regulations to insure bad chemicals are properly handled or not at all. I don't think there's any serious opposition to this plan except from some of the giant chemical producer multinationals.

Airborne Pollution

The original clean air act of the conservatives did not contain significant regulations on CO2 emissions. Instead, it mostly was oriented around regulating smog and particle pollution. The opposition parties conspired to insert an amendment that would force the government to meet Kyoto-treaty targets. This caused a great deal of political posturing on both sides of the aisle, as I talked about previously.

The Conservatives then turned back around and came up with their own plan: a 20 % reduction in greenhouse gas emissions (from 2007 levels) by 2020. It's hard not to notice how similar these numbers are in terms of timescale and reduction to Kyoto, but with everything pushed forward a decade. Kyoto originally came into effect in 1997, when the Liberals were in power.

I have not yet had the time to review this piece of legislation, but criticism has been fierce. If we ignore the political attacks, one of the most vitriolic critics is David Suzuki, who has every right to vent criticism. He essentially seems to think that the act is a sham. Al Gore has also been critical, pointing out that the bill language contains references to 'intensity reductions'. The idea behind 'intensity reductions' is that greenhouse gas producing industries are allowed to produce as much as they can sell, but they have to improve the efficiency of their processes. I.e. for every ton of aluminium you smelt, or bitumen you refine, you need to progressively improve the efficiency of the process. I'm a little of two minds on this: for one, this seems like a weasel way out. On the other hand, it seems logical that we should place the onus for reducing consumption on consumers and not producers. I'm sure once I have an opportunity to read the legislation I'll have more to say but as of today the government's website still is carrying the old version of bill C-30.

Transportation

The ecoTransport program appears to establish or repackage a number of public outreach programs surrounding public transport, personal automobiles, and commercial fleets. More importantly, it also contains a feebate program. Fuel efficient vehicles will receive a rebate of $2000 - $1000 depending on their efficiency numbers. There is a separate category for trucks, which will limit the effectiveness of the program. Much less publicized is an excise tax on gas-guzzlers. It's not a terribly aggressive tax but it does slap the Nissan Armada for $3000 and Hummer H3 for $2000.

Unfortunately, this program is hurt by the fact that E85 flex-fuel vehicles will also receive a $1000 rebate. It simply isn't possible to fuel a vehicle in Canada with E85 and it stands to reason that you never will (noting the biofuels initiative goal of E5 by 2010). Even if you think the energy return on ethanol is positive, it's extremely unlikely that supply will ever be sufficient to exceed E10; I don't see the point in paying GM to install ethanol-compatible hardware in their cars to compensate them for their piss-poor fuel economy engineering and design choices.

Another substantial policy change for ecoTransport is a $150 tax credit towards the purchase of public transit passes. This does two things: it helps reduce the relatively high marginal cost of riding public transportation rather than driving an existing car, and more importantly it gives the student councils at universities and colleges an effective tool to continue to push forward with universal transit pass schemes. I'm certainly a believer in getting students to ride transit early in their lives before they become habituated towards driving everywhere and grow fat.

Energy Efficiency

The ecoEnergy program is mostly composed of energy efficiency programs. However, there is a 1 ¢/kWh, 10-year subsidy for renewable power. This subsidy has a minimum entry level of 1 MW with fixed capacity factors, so it's not going to be applicable to solar cells on the roof of someone's garage.

The most important items, from the prospective of Joe Average, are the grant programs for home efficiency, solar-thermal water and space heating. There's up to $5000 (at a 25 % subsidy) available towards home retrofits and $300-1600/m2 for solar water heating systems (evacuated tube collectors being the high end). Unfortunately, there does not appear to be a specific program for ground-source heat pumps. A lot of construction in Canada still has baseboard electric heating, and in a subzero winter environment the ground-source heat pump is the most efficient solution but it comes with a big attached capital cost.

On the issue of energy efficiency of various appliances I feel that more could be done. There have been a pair of amendments to energy efficiency standards recently by the Conservative government but they mostly add more categories (i.e. wine chillers) than apply some meaty standards for the big consumers, like air conditioners and refrigerators. Also, how about a labeling requirement for vampire electric power consumption? A new development that is related to this proposal is a proposed ban on incandescent lighting by 2012.

Conclusion

On the question of genuine or greenwashing, I think the ecoAction program comes down on the genuine side. There's pork, there's loopholes (E85 cars), there's questionable methodology ('intensity reduction'), but there's also a ton of good stuff with billions of real money allocated towards it.

Overall, from a policy wonk perspective, the mechanisms seem solid and comprehensive. This package covers a lot of new ground so there is bound to be a lot of niggling criticisms from all corners of the political spectrum; I don't see the need to protest too much. I also think that this policy, as it is derived from the Conservative party, is a worth more than it seems on first inspection. The goalposts have been moved along the green-brown line, and that's a helpful thing.

The reason why I don't grade it any higher is simply due to the lack of zeal. It's true that Canada previously had little in the way of federal environmental or energy policy. It's also true that most citizens can only accept change so quickly. However, I think it's clear that a lot of the dollar values could easily be doubled. For example, a public transit pass costs $30-45 a month, whereas the government is only offering a $150 annual tax deduction. How would we pay for these programs you ask? Well, through the $20/ton carbon dioxide tax that the government doesn't want to implement of course.